On 21.11.2017 18:42, Christian Borntraeger wrote:
>
>
> On 11/21/2017 04:18 PM, David Hildenbrand wrote:
>> On 21.11.2017 16:08, Christian Borntraeger wrote:
>>> Old kernels did not check for zero in the irq_state.flags field and old
>>> QEMUs did not zero the flag field when calling KVM_S390_*_IRQ_STATE.
>>> Let's add a comment and dummy code to prevent future usage of flags
>>> and pad.
>>>
>>> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
>>> ---
>>> arch/s390/kvm/kvm-s390.c | 14 ++++++++++++++
>>> 1 file changed, 14 insertions(+)
>>>
>>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>>> index 6a5e02f..1baa393 100644
>>> --- a/arch/s390/kvm/kvm-s390.c
>>> +++ b/arch/s390/kvm/kvm-s390.c
>>> @@ -3834,6 +3834,16 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
>>> r = -EINVAL;
>>> break;
>>> }
>>> + if (irq_state.flags) {
>>
>> I don't see the need for if (do I need more coffee?).
>
> It is a dummy construct that matches other checks like "if flags return -EINVAL". But since
> it is dummy we can do whatever we want (even just a comment) since nobody reads flags as of
> today.
Not sure if changing the code here really makes sense ... I think I'd
rather prefer to add a comment to the header where the struct is
defined, and add some proper sentences about "flags" to the api.txt file.
Thomas
